The Collaborative International Dictionary of English v.0.48:

Ambrosiaceae \Ambrosiaceae\ prop. n.
   1. 1 in some classifications considered a separate family
      comprising a subgroup of the Compositae including the
      ragweeds.

   Syn: family Ambrosiaceae.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Ambrosiaceae
    n 1: in some classifications considered a separate family
         comprising a subgroup of the Compositae including the
         ragweeds [syn: Ambrosiaceae, family Ambrosiaceae]